Distribution characteristics of phytoplankton functional groups and their relationship with environmental factors in Taihu Basin

太湖流域地处长江下游，水系发达，是典型的平原水网地区，为明确空间和环境因子对太湖流域浮游植物功能类群分布的影响，本研究于2019年8—9月期间比较太湖流域包括河流、湖泊和水库的85个采样点的浮游植物、空间和环境特征. 首次利用“人工智能图像识别技术”，并结合传统人工镜检，共鉴定浮游植物250个分类单位，隶属于9门13纲28目57科110属，以绿藻门(45.6%)、硅藻门(19.2%)和蓝藻门(16.4%)为主. 共划分功能类群31个，包括M、D、J、S1、C、Y、F、P、MP、H1、SN、W1、G、K和TB共15个优势功能类群. 结果表明：1)太湖流域不同水体功能类群组成差异显著，差异主要来自M、J、S1、Y、P、H1类群；2)浮游植物功能类群分布具有一定的空间异质性，以太湖为中心向外形成3个聚类组，物种组成类型依次为蓝藻型、蓝藻-绿藻-硅藻型、绿藻-硅藻-蓝藻型，主要贡献类群依次为M、S1类群，M、S1、P、J类群，P、S1、J、D、C类群；3)在太湖流域，相对于环境因子而言，空间因子对浮游植物功能类群组成的影响更大. RDA分析表明，CODMn、NO3--N、TN、SD、pH值和DO与太湖流域浮游植物优势功能类群呈显著相关. 过去十年，以控源截污为主导的环境管理政策已在太湖流域取得显著成效，但是对于以M、S1类群水华为特征的夏季太湖流域而言，蓝藻水华防控仍是必须面对的难题，有机污染物和氮的控制仍是关注重点，不同水体类型和浮游植物功能类群因地制宜的管控模式仍是关键.;The study area locates in the Taihu Basin, and it spans across three provinces (Jiangsu, Zhejiang, Anhui) Shanghai Administrative Region. We sampled at 85 sites during Aug. Sep. 2019, including lakes, rivers, streams reservoirs, to investigate effects of spatial environmental factors on distribution characteristics phytoplankton functional groups (PFG) Basin. A total 250 taxa, belonging 9 phyla, 13 classes, 28 orders, 57 families 110 genera, were identified by artificial intelligence image recognition technology for first time, combined with traditional microscopy. The species composition was dominated Chlorophyta (45.6%), followed Bacillariophyta (19.2%) Cyanophyta (16.4%). According PFG classification method, 31 identified, respectively, dominant function M, S1, C, D, Y, G, MP, P, J, SN, F, TB, K, H1 W1. results showed that: 1) There significant differences among different water bodies mainly from P groups; 2) Basin certain heterogeneous, cluster found. Moreover, corresponding types are Cyanophyta, Cyanophyta-Chlorophyta-Bacillariophyta Chlorophyta-Bacillariophyta-Cyanophyta. M S1 groups, j D C respectively; 3) Spatial factor plays a major role formation community than Redundant analysis that CODMn, NO3--N, TN, SD, pH DO main affecting distribution. Over past decade, management policy led source pollution control has achieved remarkable Basin; however, more effective prevention methods expected propose controlling cyanobacterial blooms future, organic pollutants nitrogen should be paid attention aquatic ecological summer. More importantly, appropriate mode adopted deal PFGs.